View single post by Tom Bradley
 Posted: 06-15-2017 06:53 am
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Tom Bradley


Joined: 07-15-2013
Posts: 114
Hi Dan,
Do you know if the tach is reading correctly at the lower RPMs? The XDi ignition system uses two coils for a 4-cyl engine instead of one. So if the signal to the tack is only coming from one coil, the RPM reading will be 1/2 of the actual engine speed unless the tach has been modified to account for this or if the XDi system is sending a separate (composite) signal to the Tach. In the latter case, the tach may be maxing out because the signal is too low and it is not picking up all the pulses at the higher rates. Possibly the tach has a sensitivity adjustment or the XDi has a signal level adjustment to correct this.